Preheat the oven to 180 degrees C. Line a 12-cup and a 6-cup cupcake tin or muffin pan with paper cupcake cases.
Place the margarine, sugar and eggs in a large bowl. Sift the white and wholemeal flours and the baking powder into the bowl, tipping in any bran left in the sieve. Add the orange rind and beat with an electric mixer for 2 minutes or until smooth and creamy.
Spoon the mixture into the paper cupcake cases. Bake for about 20 minutes or until the centres of the cakes are just firm to the touch. Transfer to a wire rack to cool. (The cakes can be stored in an airtight container for up to 2 days before being iced.)
To make the icing, place the ricotta in a bowl and sift over the icing sugar. Add the orange rind and beat with a wooden spoon until well mixed.
Spread a little icing over the top of each cake and decorate with a couple of dried apricot slices. Serve as soon as possible after icing.